About

This is an improved PCI fan holder for the Mac Pro 5,1, allowing for longer GPUs such as the Radeon RX 6800 XT and 6900 XT, where many models are too long to fit in the case.

This designs removes the stock PCI fan cage and replaces it with a slim fan holder positioned further to the front of the case, allowing fitment of GPUs up to around 350 mm long. I'm using a PowerColor Radeon RX 6900 XT 16GB Red Devil Ultimate which is 320 mm long and it easily fits, see the picture at the bottom.

The fan connector slides in place into the new mount where it is secure and the mount uses the same mounting screws as the original. For the mount I recommend using M3 heated inserts where the fan is attached but you can use M3 or M4 screws and nuts as well. I don't recommending using the stock silicone straps as they are too flimsy when attached to this design.

Print settings

Print the mount in the direction I have set it. Supports are not needed. Use a minimum of 4 walls and 25% infill so it's rigid enough.

I recommend printing it in high temp resistant filament like PC, for example Prusament PC-CF which I've used here. Another good option is Polymaker PolyMax PC-FR which is flame retardant. I would not use PLA, it's not heat resistant enough so it could bow down from the heat. PETG should be OK.

Buy a prebuilt mount

If you're looking for a prebuilt mount with included screws, here is an authorized reseller *:

• Motor City 3D Print (United States)

* 4€ for each sold unit is donated to the designer to help development with this and other designs.

Remove the stock PCI fan cage

First off, disconnect the power cable to your Mac Pro and open the case. Remove the current GPU and also the drive bays so you get some working space. Unscrew the PCI fan cage, it is attached with two small black Phillips screws on the right hand side. Then slide it out carefully, you might need to wiggle it a little.

Unscrew the two small silver hex screws sitting inside the fan cage. Next, you can slide out the inner housing from the outer housing by applying some pressure on one side (see picture below) while pressing the white button, the outer casing is quite flexible. There is a dovetail clip inside you need to slide over. It's not difficult, just take your time.

Now with the inner casing removed you can just pull out the black silicone straps holding the fan in each corner and slide out the fan connector from its mount.

Assembling the new mount

I use two M3 heated inserts for the fan holes but you can use M3 or M4 screws and nuts as well.

Next, position the fan like this then slide in the fan connector.

Screw the fan to the mount using two screws.

All done with the mount:

Installing the new mount

First push in the fan connector so the mount rests on it.

Next, attach the two black Phillips screws to secure the mount.

Install the GPU and slide over the metal bar that secure the PCI-express slot. If you can't reach it (other PCI cards in the way for example) you can also push the small metal rod circled in the picture below, it's just below the custom mount.

Use some zip-ties to the get the cables away for best airflow. All done!

Support

All my designs and mods are free to use and remix. They have a non-commercial license. If you enjoy this or any of my other designs you can send me a small donation using the link below. Thanks :)

• https://www.paypal.me/humebeamengineering